Brake fade???? Has anyone experienced this before?

[Charger 1]

Here's my problem:  under normal driving, the brakes stop the car fine.  However, if I try to stop the car quickly from highway speeds or faster, you hit the pedal, it travels its normal distance, the front of the car noses downwards like I think it should, then the braking just quits, as if you let off of the pedal.  Pushing on the pedal harder makes no difference when this is happening.  You can release the pedal immediately and smash it again and the same thing happens.  The car is a '69 Charger with factory power drums all the way around.  The red brake in the dash is all the time - that's why I leave the wire off of the proportioning valve.  Any ideas?  If the proportioning valve is bad, could that be the cause?  Any help will be GREATLY appreciated!!  

[Ghoste]

Stupid question, but what is your fluid level at?

[Nacho-RT74]

If light is turning on and you ARE SURE don't have leak, definitelly damaged brake dist block assembly. Have you noticed if brake fluid is being transfered from one to the other deposit being sure master cilinder is perfect ?

( I have dealt with that kind of weird stuff twice in 4 years, even with the new repro unit being sold )

[Charger 1]

Fluid level is full and I never have to add any.  Master cylinder is a reman unit about 3yrs old.  I will pull it away from the booster tonight to verify that there is no fluid transfer.

[Charger 1]

Also, the light isn't 'turning on' - it is on steady as long as I leave the wire plugged onto the proportioning valve.

[Nacho-RT74]

Also, the light isn't 'turning on' - it is on steady as long as I leave the wire plugged onto the proportioning valve.

well of course thats why I mean LOL... imposible to get it ON if is unplugged. They will turn on just by the emergency brake pressed.

[Nacho-RT74]

Fluid level is full and I never have to add any.  Master cylinder is a reman unit about 3yrs old.  I will pull it away from the booster tonight to verify that there is no fluid transfer.

by fluid transfer I mean between front and rear deposit, not really to the brake booster. However if you already removed master cilinder cap and never noticed diff, thats not a problem. I had once overfowed rear brakes deposit and front brakes getting emptied

[elacruze]

Is the pedal hard all the time? Does it change feel during these events?
Sounds like your pressure differential valve may be stuck.
Could just be old hard crappy brake shoes. How old are they?

[Charger 1]

The brake pedal is never hard as in a 'no vacuum to booster' hard.  No, the feel does not change during these events.  Like I said, during normal driving, the brakes work fine.  It's just whenever you try to stop quickly, like a panic stop, the pedal travels its normal 1 - 2", the car nosedives, like the brakes are grabbing, then the car acts like I just released the pedal even though I didn't.  I even try to push harder when this happens and the pedal won't move any further.

As for the age of the shoes, I have no idea.

[Charger-Bodie]

Drum brakes do tend to fade during a hard stop. They dont get rid of heat like discs do. Im not sure if what you are describing is normal or not but they do fade.

Are your brakes 10x2s or 11x3s?

[Charger 1]

10 x 2s

I wondered about brake fade.  I've heard about it before, but I have never really experienced it.  I've thought about doing a disc brake conversion.  Last fall, we parted out a '78 Cordoba and I kept the spindles, calipers, proportioning valve, and master cylinder.  I've heard some say these parts will work - others say find parts from a '73 - '73 a-body.  I don't have a problem doing the swap - I would just like to know exactly what is wrong with the car now.  As far as brake fade goes, is this how the cars were from the factory? 

[elacruze]

10 x 2s

I wondered about brake fade.  I've heard about it before, but I have never really experienced it.  I've thought about doing a disc brake conversion.  Last fall, we parted out a '78 Cordoba and I kept the spindles, calipers, proportioning valve, and master cylinder.  I've heard some say these parts will work - others say find parts from a '73 - '73 a-body.  I don't have a problem doing the swap - I would just like to know exactly what is wrong with the car now.  As far as brake fade goes, is this how the cars were from the factory?  

Holy Moly, you already have all the conversion parts...disc brakes are a no-brainer. If you don't know the age of your shoes, they're junk and weren't much good when new. At the very least replace them, surface the drums and replace the brake fluid. The brake warning light on the dash could simply be a shorted wire. Test the circuits and the switch.

Man, if it was me I'd make the swap. Oh wait, I did!  
I used the late Cordoba spindles brackets and calipers, with Firmfeel tubular upper control arms to get some caster and eliminate worry about balljoint angle. I also bought 11-3/4" rotors and had them cryo treated from www.frozenrotors.com .

Brake fade is horrible on drums. Disc brakes fade too, but not as badly. I was in my buddy's '74 396 Camaro rolling through central Michigan at about 140mph in the middle of the night. He spotted deer eyes in the road way up ahead and stepped on the brakes with both feet. The tires howled for about a second and a half, then just like you said the car felt like he'd let off the pedal. I bet we were still going 90 when we went past that deer...

[Blown70]

10 x 2s

I wondered about brake fade.  I've heard about it before, but I have never really experienced it.  I've thought about doing a disc brake conversion.  Last fall, we parted out a '78 Cordoba and I kept the spindles, calipers, proportioning valve, and master cylinder.  I've heard some say these parts will work - others say find parts from a '73 - '73 a-body.  I don't have a problem doing the swap - I would just like to know exactly what is wrong with the car now.  As far as brake fade goes, is this how the cars were from the factory? 

My current 318 car has disc, they are not as bad as you speak of, but they are not what I LIKE to drive in traffic..... I would suggest a lot of us have become used to the new vehicles, then when we drive our older ones,  its a big change....

DO THE DISCs, you will love the converstion...

[Charger-Bodie]

10 x 2s

I wondered about brake fade.  I've heard about it before, but I have never really experienced it.  I've thought about doing a disc brake conversion.  Last fall, we parted out a '78 Cordoba and I kept the spindles, calipers, proportioning valve, and master cylinder.  I've heard some say these parts will work - others say find parts from a '73 - '73 a-body.  I don't have a problem doing the swap - I would just like to know exactly what is wrong with the car now.  As far as brake fade goes, is this how the cars were from the factory? 

10x2 brakes will of course be even worse.

[RECHRGD]

I've got front discs on my current Charger.  BUT, my original (new) '68 R/T had the H.D. power 11" drums.  As I recall the brakes were always junk from the day I bought the car to the day I sold it, some 35,000 miles later.  I had the drums turned repeatedly and some were replaced.  Had new pads put on at least twice and nothing ever got better.  They would fade after a short time of braking at speed, but were basically fine at low speed.  At speeds over 70mph, it was like I had no brakes at all.  HMMM, now I'm wondering why the heck I bought another Charger so many years later.   Bob

[ZSmithersCharges]

How old are your brake lines?  I just read an article in automobile mag (I think it could be another publication) about how your supposed to change brake lines every couple of years if they are not steel braided as the material they are made out of bulges under regular braking and even more so under hard braking.  What ends up happening is the lines get weakened and this leads to the brake fade feel but it is really just the lines expanding under hard braking eventually leading to catastrophic failure ie. the lines exploding. What everyone else said is great as well and if nothing else replace your lines when you do the disc brake swap cause honestly... F*ck drum brakes... I dont even know why they still put them on cars.

[bordin34]

If you have all those parts put the discs on. I can lock up all 4 tires at slow speeds and brake from 60-30 like any newer car. Somebody pulled out in front of me on the highway a couple weeks ago and I locked up the rears and the car stopped great, didn't notice any fade.

[Silver R/T]

check your brake fluid also to see level of contamination. They have electronic tester for that

[GT]

Been there done that.  four wheel manual 10x2" drums on my charger.  One good stop from 65 and you were done - hope you didn't have to stop again in 15min.  Scared me more than once.  Those brakes were inadequate when new.    Stepping up to four wheel 14" Wilwood disks.  Decided to not screw with it anymore if I was gonna run a viper motor.

[c00nhunterjoe]

mine fade horrible too, from 110 mph i use every bit of the half mile shut down lanes at the drag strip on the pedal as hard as i can push

[hemi-hampton]

Nothing more scarry then coming up on a green light at 100 mph that suddenly turns Red on you & you hit the brakes hard just to find out you got nothing, total brake Fade & as you watch the cars passing in front of you you pray you dont hit any of them   LEON.

[Charger 1]

I thought that I would pass along the latest with my 'brake fade' issue.  While I do have all the parts off of the '78 Cordoba to do a disc brake conversion, I wanted that to be a last resort.  What I mean by that is that I'm not wanting to retain drum brakes for the 'original' look, I just wanted to see if I could make the car stop with them.  I just can't believe that all these cars factory equipped with drums brakes couldn't stop a car quickly from high speeds.  So, here's what I did.

First, I replaced the front shoes, wheel cylinders, brake hoses, and spring kit and machined the drums - this made no difference in braking - the car still would not stop quickly from high speeds.

Secondly, I replaced the brake distribution block - this made no difference in braking - the car still would not stop quickly from high speeds - this did however keep my red brake light from coming on.

Next, I replaced the brake booster with a reman unit from A1 Cardone - this made no difference in braking - the car still would not stop quickly from high speeds.

After I replaced the brake booster (for no apparent reason), I contacted a tech at A1 Cardone and asked him if he had ever heard of this condition.  He said that he hadn't but did ask me how much vacuum my engine produced.  I told him 13-14".  He said that a booster will not operate properly without at least 17" of vacuum.  Then it dawned on me that a good friend of mine has a '67 Charger with 10" drums all the way around - non power.  I asked him how his car stops under these conditions and he said that he has never had to and has never tried to stop his car quickly from high speeds.  So we immediately jumped into his car and went out of town a few miles, reached 90 mph and stood on the brakes and set that car down right now.  We ran it right back up to 90 and did it again - same thing.  As a matter of fact, he did this four times in a row and then jumped out and let me do it two more times.  That was a total of six times in a row - back to back - 90 mph to zero - no brake fade at all.  If you pressed too hard on the pedal, the brakes would actually lock up and the car would start sliding.  I immediately went home and removed my brake booster and installed the correct firewall plate and pedal linkage.  Took the car out and guess what?  The car stops like it should - no brake fade - I can actually lock up the brakes.  The pedal feels great.  I took the car to St. Louis for Monster Mopar - no issues - I couldn't be happier.

Now, I'm not trying to talk anyone out of doing a disc brake conversion.  I just wanted to prove to myself that an old car with drum brakes WILL stop quickly from high speeds.  I never really considered 13-14" of vacuum to be too low, but there must be something to it.  Of course, the other side of this coin is that I'm sure that there are those out there that have done the disc conversion with power and have no stopping issues.  

Anyway, I just thought that I would share this.  Maybe this info can help someone else.  

[alcusswhen]

Here's my problem:  under normal driving, the brakes stop the car fine.  However, if I try to stop the car quickly from highway speeds or faster, you hit the pedal, it travels its normal distance, the front of the car noses downwards like I think it should, then the braking just quits, as if you let off of the pedal.  Pushing on the pedal harder makes no difference when this is happening.  You can release the pedal immediately and smash it again and the same thing happens.  The car is a '69 Charger with factory power drums all the way around.  The red brake in the dash is all the time - that's why I leave the wire off of the proportioning valve.  Any ideas?  If the proportioning valve is bad, could that be the cause?  Any help will be GREATLY appreciated!!  

You have a bad master cylinder. I'll bet a 440 push rod to a 318 piston than if you unbolt the master from the booster the back of it will be wet.

[elacruze]

If your brakes satisfy your driving requirements, and you're certain that everything is in good working order (which yours now obviously is) drums are fine. I'm not sure I'd go to the trouble myself if I didn't think my usage required and upgrade.
On my car I was never satisfied with the feel of the brakes, and in particular it was sensitive to misadjustment; every time the adjuster would click over on one side or the other it would pull a (tiny) bit to one side or the other, then change when the other side adjusted up. I wasn't too concerned that I had styrofoam from a cooler to fill the hole in my seat, but I'm a Nazi when it comes to drivabilty details. I'm upgrading my entire front suspension/brakes so I can get the geometry where I want it and have smooth easy to drive brakes that have reserve capacity.

Drums do have many years of performance research behind them-you can buy performance shoes from Ferodo, at least you could years ago for the big R/T drums. You can have the drum bored and relined with a higher-coefficient liner, and have the diameter bored to the same radius as the shoes for full contact. That said, drums that are race-prepped are usually uncomfortable to ride (or drive) at street speeds; they are grabby and senstive.

I guess to answer the question you didn't really ask, yes drums can stop a car well more than once, but will never be quite as good as discs of similar quality in any particular situation.

[Charger 1]

Here's my problem:  under normal driving, the brakes stop the car fine.  However, if I try to stop the car quickly from highway speeds or faster, you hit the pedal, it travels its normal distance, the front of the car noses downwards like I think it should, then the braking just quits, as if you let off of the pedal.  Pushing on the pedal harder makes no difference when this is happening.  You can release the pedal immediately and smash it again and the same thing happens.  The car is a '69 Charger with factory power drums all the way around.  The red brake in the dash is all the time - that's why I leave the wire off of the proportioning valve.  Any ideas?  If the proportioning valve is bad, could that be the cause?  Any help will be GREATLY appreciated!!  

You have a bad master cylinder. I'll bet a 440 push rod to a 318 piston than if you unbolt the master from the booster the back of it will be wet.

Sorry, wrong answer.  The rear of the master cylinder and the front of the booster were dry as toast!!  As a matter of fact, I'm using the same master cylinder.  I just installed the studs and rear retainer for the pushrod boot.